Chaste Tree Berry Herb: Chaste tree berry herb reads the individual body's hormonal scape via the hypothalamus and acts accordingly to bring balance. Chaste tree berry also has been shown to have a stimulating effect on dopaminergic neurons, which is important for horses with Cushing's as this disease is caused by a loss of the dopaminergic neurons of the hypothalamus. Insulin is an endocrine hormone; by naturally balancing hormones, insulin resistance subsides.